Gas Relative Permeability and its Evolution During Water Imbibition in Unconventional Reservoir Rocks: Direct Laboratory Measurement and a Conceptual Model
- Sheng Peng (Bureau of Economic Geology, University of Texas at Austin)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- November 2019
- Document Type
- Journal Paper
- 1,346 - 1,359
- 2019.Society of Petroleum Engineers
- water redistribution during shut-in, relative permeability, water block effect, unconventional reservoir, fracture-matrix intera
- 6 in the last 30 days
- 165 since 2007
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Relative permeability has a significant impact on gas or oil and water production, and is one of the most complicated properties in unconventional reservoirs. Current understanding of relative permeability for unconventional reservoir rocks is limited, mainly because of a lack of direct measurement of relative permeability for rocks that have a matrix permeability at the submicrodarcy level. Because of the difficulties related to direct measurement, most studies on relative permeability in unconventional reservoirs are based on indirect or modeling methods. In this paper, a modified gas-expansion method for shale matrix-permeability measurement (Peng et al. 2019) was adopted to measure gas relative permeability directly under the scenario of water imbibition for samples from different unconventional reservoir formations. Evolution of gas permeability, along with gas porosity and fracture/matrix interaction, during the process of water redistribution (which mimics what occurs in the shut-in period in real production) was also closely measured. Results show that gas relative permeability in the matrix decreases during water redistribution because of water imbibition from fractures to the matrix coupled with a water-block effect. The water-block effect is more significant at low water saturations than at higher water saturations, leading to a rapid-to-gradual drop of gas relative permeability with increasing water saturation.
A conceptual model on water redistribution in a fracture/matrix system and the change of gas and water relative permeability is proposed on the basis of experimental results and observations. Influencing factors including pore size, shape, connectivity, and wettability are taken into account in this conceptual model. The combined effect of these four influencing factors determines the level of residual gas saturation, which is the most important parameter in defining the shape of relative permeability curves. Water relative permeability is predicted on the basis of the conceptual model and the measured gas relative permeability using modified Brooks-Corey equations. Deducing the oil/water relative permeability is also discussed. The implications of relative permeability for gas or oil and water production and potential strategies for optimal production are also discussed in the paper. The hysteresis effect is not included in this study but will be addressed in future work.
|File Size||870 KB||Number of Pages||14|
Avraam, D. G. and Payatakes, A. C. 1995. Generalized Relative Permeability Coefficients During Steady-State Two-Phase Flow in Porous Media, and Correlation With the Flow Mechanisms. Transport Porous Med 20: 135–168. https://doi.org/10.1007/BF00616928.
Brooks, R. H. and Corey, A. T. 1966. Properties of Porous Media Affecting Fluid Flow. J Irrig Drain Div 6 (61): 61–90.
Cantisano, M. T., Restrepo, D. P., Cespedes, S. et al. 2013. Relative Permeability in a Shale Formation in Colombia Using Digital Rock Physics. Presented at SPE/AAPG/SEG Unconventional Resources Technology Conference, Denver, Colorado, 12–14 August. URTEC-1562626-MS. https://doi.org/10.1190/urtec2013-092..
Chatzis, I., Morrow, N. R., and Lim, H. T. 1983. Magnitude and Detailed Structure of Residual Oil Saturation. SPE J. 23 (2): 311–326. SPE-10681-PA. https://doi.org/10.2118/10681-PA.
Dacy, J. M. 2010. Core Tests for Relative Permeability of Unconventional Gas Reservoirs. Presented at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 September. SPE-135427-MS. https://doi.org/10.2118/135427-MS.
Daigle, H., Ezidiegwu, S., and Turner, R. 2015. Determining Relative Permeability in Shales by Including the Effects of Pore Structure on Unsaturated Diffusion and Advection. Presented at the SPE Annual Technical Conference and Exhibition, Houston, Texas, 28–30 September. SPE-175019-MS. https://doi.org/10.2118/175019-MS.
Ehrlich, R. 1993. Viscous Coupling in Two-Phase Flow in Porous Media and Its Effect on Relative Permeabilities. Transp Porous Med 11: 201–218. https://doi.org/10.1007/BF00614812.
Honarpour, M. M., Nagarajan, N. R., Orangi, A. et al. 2012. Characterization of Critical Fluid PVT, Rock, and Rock-Fluid Properties: Impact on Reservoir Performance of Liquid Rich Shales. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 8–10 October. SPE-158042-MS. https://doi.org/10.2118/158042-MS.
Kausik, R., Fellah, K., Rylaner, E. et al. 2014. NMR Petrophysics for Tight Oil Shale Enabled by Core Resaturation. Presented at the International Symposium of the Society of Core Analysts, Avignon, France, 8–11 September. SCA2014-073.
Landry, C. J., Prodanovic, M., Reed, R. et al. 2017. Estimating Oil-Water Relative Permeability Curves Using Digital Rock Physics. Presented at the SPE/AAPG/SEG Unconventional Resources Technology Conference, Austin, Texas, 24–26 July 2017. URTEC-2691701-MS. https://doi.org/10.15530/URTEC-2017-2691701.
Lenormand, R., Zarcone, C., and Sarr, A. 1983. Mechanisms of the Displacement of One Fluid by Another in a Network of Capillary Ducts. J Fluid Mech 135: 337–353. https://doi.org/10.1017/S0022112083003110.
Middleton, R. S., Gupta, R., Hyman, J. D. et al. 2017. The Shale Gas Revolution: Barriers, Sustainability, and Emerging Opportunities. Appl Energ 199 (August): 88–95. https://doi.org/10.1016/j.apenergy.2017.04.034.
Moghaddam, R. N. and Jamiolahmady, M. 2019. Steady-State Relative Permeability Measurements of Tight and Shale Rocks Considering Capillary End Effect. Transp Porous Med 128: 75–96. https://doi.org/10.1007/s11242-019-01236-8.
Nicot, B., Vorapalawut, N., Rousseau, B. et al. 2015. Estimating Saturations in Organic Shales Using 2D NMR. Presented at the International Symposium of the Society of Core Analysts, St John’s, Newfoundland and Labrador, Canada, 16–21 August. SCA 2015-024.
Ojha, S. P., Misra, S., Tinni, A. et al. 2017. Relative Permeability Estimates for Wolfcamp and Eagle Ford Shale Samples From Oil, Gas and Condensate Windows Using Adsorption Desorption Measurements. Fuel 208: 52–64. https://doi.org/10.1016/j.fuel.2017.07.003.
Peng, S. and Loucks, B. 2016. Permeability Measurements in Mudrocks Using Gas-Expansion Methods on Plug and Crushed-Rock Samples. Mar Petrol Geol 73 (May): 299–310. https://doi.org/10.1016/j.marpetgeo.2016.02.025.
Peng, S., Ren, B., and Meng, M. 2019. Quantifying the Influence of Fractures for More Accurate Laboratory Measurement of Shale Matrix Permeability Using a Modified Gas Expansion Method. SPE Res Eval & Eng 22 (4): 1293–1304. SPE-195570-PA. https://doi.org/10.2118/195570-PA.
Peng, S., Zhang, T., Loucks, R. et al. 2017. Application of Mercury Injection Capillary Pressure to Mudrocks: Conformance and Compression Corrections. Mar Petrol Geol 88 (December): 30–40. https://doi.org/10.1016/j.marpet.geo.2017.08.006.
Purcell, W. R. 1949. Capillary Pressures—Their Measurement Using Mercury and the Calculation of Permeability Therefrom. J Pet Technol 1 (2): 39–48. SPE-949039-G. https://doi.org/10.2118/949039-G.
Standnes, D. C., Evje, S., and Andersen, P. P. 2017. A Novel Relative Permeability Model Based on Mixture Theory Approach Accounting for Solid-Fluid and Fluid-Fluid Interactions. Transp Porous Med 119: 707–738. https://doi.org/10.1007/s11242-017-0907-z.
Tuller, M. D. and Or, D. 2001. Hydraulic Conductivity of Variably Saturated Porous Media: Film and Corner Flow in Angular Pore Space. Water Resour Res 37 (5): 1257–1276. https://doi.org/10.1029/2000WR900328.
Yassin, M. R., Dehghanpour, H., Wood, J. et al. 2016. A Theory for Relative Permeability of Unconventional Rocks With Dual-Wettability Pore Network. SPE J. 21 (6): 1970–1980. SPE-178549-PA. https://doi.org/10.2118/178549-PA.
Yuster, S. T. 1951. Theoretical Considerations of Multiphase Flow in Idealized Capillary Systems. Presented at the 3rd World Petroleum Congress, The Hague, The Netherlands, 28 May_6 June. WPC-4129.